Non-Pyrophoric Pt-Ce Catalyst for Water-Gas Shift
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Solution Overview
Problem
Current catalysts for low-temperature water-gas shift reactions, such as Cu—Zn based catalysts, are pyrophoric and require inert gas protection, limiting their stability and activity, especially during fuel processor start-up and shut-down cycles, and struggle to maintain low CO concentrations below 5,000 ppm.
Innovation Solution
A non-pyrophoric water-gas shift reaction catalyst comprising zirconium oxide (ZrO2) with yttrium oxide (Y2O3) and cerium oxide (CeO2) as an oxide carrier, supported with platinum (Pt) and cerium (Ce), which is prepared by mixing precursors and sintering, allowing for high activity and stability at temperatures below 230°C without the need for nitrogen purging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Cu-Zn based catalyst is used for low temperature shift reaction, then reaction activity at low temperature is improved, but pyrophoric property causes stability deterioration and requires inert gas protection
Solution Approach 1:
The catalyst composition is changed from Cu-Zn based to Pt-Ce based on zirconium oxide carrier, fundamentally altering the chemical and physical parameters of the catalyst to eliminate pyrophoric properties while maintaining low-temperature activity. This parameter change resolves the contradiction by selecting materials with inherently different safety characteristics.
Solution Approach 2:
A composite catalyst system is created combining Pt and Ce on a zirconium oxide carrier, synergistically achieving both high reaction activity and non-pyrophoric stability. The composite structure allows the zirconium oxide carrier to provide thermal stability and safety while Pt-Ce active sites deliver catalytic performance.
2Reliability
If shift reaction is performed slowly to maintain Cu-Zn catalyst activity and stability, then catalyst reliability is improved, but reaction time increases
Solution Approach 1:
By changing the catalyst type to Pt-Ce on zirconium oxide, the reaction can proceed rapidly without the stability constraints that limit Cu-Zn catalysts. The new catalyst parameters enable both high activity and stability simultaneously, eliminating the need for slow reaction rates.
3Reliability
If inert gas is injected to protect Cu-Zn catalyst during start-up and shut-down, then catalyst stability is improved, but device complexity increases
Solution Approach 1:
Changing the catalyst material properties from pyrophoric Cu-Zn to non-pyrophoric Pt-Ce on zirconium oxide eliminates the need for inert gas protection systems during start-up and shut-down operations, thereby reducing device complexity while maintaining catalyst stability.
4Reliability
If conventional two-step shift reaction process is used, then CO removal efficiency is improved, but process complexity increases
Solution Approach 1:
The Pt-Ce catalyst on zirconium oxide carrier combines the functions of high-temperature and low-temperature shift reactions into a single catalyst and reactor stage, eliminating the need for separate high-temperature and low-temperature shift reactors and simplifying the overall process while maintaining CO removal efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The catalyst achieves high CO conversion rates with low CO exit concentrations, maintaining activity and stability over time, even when exposed to air, and can operate in a single-step shift reaction, effectively replacing conventional two-step processes.
Implementation Method 1
platinum (Pt) and cerium (Ce) that are supported on the oxide carrier
Implementation Method 2
sintering the dried resultant
Data Source
AI summary
Provided are a non-pyrophoric water gas shift reaction catalyst including: an oxide carrier composed of zirconium oxide (ZrO2) and at least one selected from yttrium oxide (Y2O3) and cerium oxide (CeO2); and platinum (Pt) and cerium (Ce) that are supported on the oxide carrier, a method of preparing the same, and a fuel processor including the non-pyrophoric water gas shift reaction catalyst.